knockout promotes paclitaxel sensitivity in drug-resistant cells induction of necrotic cell death.

Autophagy regulators are often effective as potential cancer therapeutic agents. Here, we investigated paclitaxel sensitivity in cells with knockout (KO) of gene. The KO in multidrug resistant v-Ha--transformed NIH 3T3 cells (Ras-NIH 3T3/Mdr) was generated using the CRISPR/Cas9 technology. The qPCR and LC3 immunoblot confirmed knockout of the gene and protein of , respectively. The KO restored the sensitivity of Ras-NIH 3T3/Mdr cells to paclitaxel. Interestingly, overexpression restored autophagy function in KO cells, but failed to rescue paclitaxel resistance. These results raise the possibility that low level of resistance to paclitaxel in KO cells may be related to other roles of independent of its function in autophagy. The KO significantly induced a G/M arrest in cell cycle progression. Additionally, KO caused necrosis of a high proportion of cells after paclitaxel treatment. These data suggest that the difference in sensitivity to paclitaxel between KO and their parental MDR cells may result from the disparity in the proportions of necrotic cells in both populations. Thus, our results demonstrate that the KO in paclitaxel resistant cells leads to a marked G/M arrest and sensitizes cells to paclitaxel-induced necrosis.